Can you solve this problem step by step for me?

Which of the following pair(s) of circles have las a common external tangent? select all that apply. a and b a and c b and c

Is a square always, sometimes, or never a parallelogram

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)